Alfv\'en Eigenmodes in a DIII-D Discharge Simulated in GYRO

Alfv\'en eigenmodes (AEs) are excited by, and cause transport of, beam or fusion energetic particles (EPs). We examine a beam-heated, shear-reversed DIII-D discharge (142111) where toroidal Alfv\'en eigenmodes (TAEs) and reverse shear Alfv\'en eigenmodes (RSAEs) flattened the beam EP density profile. With the gyrokinetic code GYRO [1], we follow low-$n$ unstable TAEs and RSAEs in this discharge. TAEs and RSAEs are tracked (with GYRO's parallel eigenvalue solver) as the minimum safety factor $q_{min}$ evolves in time. RSAE frequency sweeping and RSAE-TAE mode-mode interaction (where the mode distinction is blurred) are observed. In this full gyrokinetic treatment, all eigenfunctions are perturbed from the canonical MHD form. Poloidal twisting [2] and on-surface peaking of poloidal harmonics (EPM-like) [3] are examples. The global transport ``footprint'' corresponds to regions of strong local drive for dominant modes, generally less so for subdominant modes.\par \vskip6pt \noindent [1] J.~Candy and R.E.~Waltz, Phys.\ Rev.\ Lett.\ {\bf 91}, 045001 (2003).\par \noindent [2] B.J.~Tobias et al., Phys.\ Rev.\ Lett.\ {\bf 106}, 075003 (2011).\par \noindent [3] E.M.~Bass and R.E.~Waltz, Phys.\ Plasmas {\bf 17}, 112319 (2010).